reporter's notebook TUCSON, Ariz.--I don't really know that much about airplanes, but I know I love them.

That's why, as I sit on the bus for a tour of the Aerospace Maintenance and Regeneration Group facility (AMARG) at Davis-Monthan Air Force base here, I'm in plane-geek heaven.

AMARG sits on more than 2,600 acres and houses more than 4,300 planes, most of them military-issue. On the other side of the road from AMARG is the , which sits on its own 155 acres and has a collection of 284 military and civilian planes.

In short, this is just about as good as it gets if you like planes, and that's why I've come here on Road Trip 2007, my tour around the Southwest in search of the best technology and science stories.

One might wonder why Tucson is ground zero for airplane storage, but it's really not that surprising. It's partly the soil, tour guides at both facilities explain, known as caliche soil, which when dry, is extremely hard but easy to put anchors into. Plus, there's tons of open space here, meaning that giving up thousands of acres to these kinds of facilities is economically viable.

I visited PASM first and was given a private tour by Scott Marchand, the museum's director of collections and airplane restoration.

He explained that the museum was chartered in 1966 for the preservation and presentation of vintage aircraft, and opened its doors in 1976. At first, it had 50 planes, but the collection has slowly grown as planes have come in from the government and other donors. PASM only owns 110 of its planes, and the rest are on loan from organizations like the Army, Navy, Air Force, NASA and the Coast Guard.

The museum is like a walking tour of modern airplane history, going back to World War II days.

In one hangar you'll find a B-29 Superfortress, the kind of plane used to drop the atomic bombs on Japan. And outside, you'll find the Boeing VC-137 known as "Freedom One," which was used to bring the American hostages home from Iran in 1981. There's also one of Howard Hughes' TWA Constellations; a B-24J Liberator heavy bomber flown by the British and then the Indian Air Force; an Aerospace 377 Superguppy, which was used to transport Saturn missiles; and so many more.

I asked Marchand which plane is his favorite. He shrugged, indicating he couldn't possibly choose.

"It's like asking what's your favorite kid," he said, seriously.

Many of the planes look pretty beat up, and it's no wonder, since they've been sitting on the desert floor for years under an unforgiving sun, "the biggest enemy we have out here," Marchand explained.

"The sun is murder on paint jobs. We're lucky if we can get 15 years" out of a paint job, he said.

But that's why the museum also maintains a repair and restoration facility. Marchand took me there and showed me how one crew was meticulously repainting a Douglass B-23 by wrapping it and painting it section by section, while another crew was working on rebuilding a Curtiss O-52 Owl, a pre-World War II Army observation plane.

Nearby, a different crew, including French college students here for three months, was reconditioning a P-51 Mustang. Marchand said the project would take nearly four years to complete.

Finished with the tour of the museum, I got on a bus with several dozen other visitors and off we went for the drive around AMARG.

This was serious airplane spotting. It's literally an hour of nonstop airplanes, which can almost be tiring. Almost.

Correction: An earlier version of this story misidentified the model of a Boeing airplane on display at AMARG. The correct model is 727.